Tape systems allow large amounts of data to be stored in a cost effective manner. Tape systems include tape cartridges, which hold tape coated with a magnetic medium, and tape decks, which contain electronics capable of writing to and reading from the magnetic tape.
Over time, heads in the tape deck responsible for writing to and reading from the tape become covered with contaminants. One source of contaminants is from the tape itself. Tape may include a substrate, back coat oxide, metal particles, mylar film, and a binder. These materials decay from the tape structure during operation and storage of the tape and form debris. During drive operation, debris migrates to areas on the tape path and transport. In particular, debris deposits onto the surface of the magnetic recording head and in the air bleed slots of the head. As debris deposits build, the tape may "fly" above read/write elements, compromising tape deck operation.
Another source of contamination on magnetic recording heads comes from "brown stains". Brown stain is thought to arise from tape decay during storage in combination with other variables. Brown stain may also cause the tape to fly above read/write elements, compromising data exchange.
As tape deck technology advances, mechanisms for cleaning tape heads must also improve. One advance in tape deck technology is the use of a high density recording dual read/write head. This head employs bleed slots perpendicular to the direction of tape travel to ensure a proper read/write interface between the head and the tape. Another advance is increased use of microelectronics. Microelectronic devices can be easily damaged by static electricity generated during cleaning operations.
Various cleaners in cartridge and cassette housings have been proposed. In particular, U.S. Pat. Nos. 4,458,281 to Kara and 4,918,557 to Lee describe devices for cleaning audio cassette player heads using a linear wiping motion in the same direction as tape travel. Such motion may cause the same grooving as cleaning tapes and, hence, is not an acceptable solution. Movement in the direction of tape travel will not adequately clean head bleed slots perpendicular to the direction of tape travel. Also, no ability to prevent or remove static electricity build-up is described.
U.S. Pat. No. 4,631,616 to Zago et al. describes an audio cassette player head cleaner. In this device, a cleaning pad is rotated such that the cleaning motion is substantially the same as tape movement over the head. Again, this may cause a buildup of debris in vertical bleed slots detrimental to tape head operation. Also, motion is not conducive to cleaning head bleed slots and static electricity build-up is not addressed.
U.S. Pat. Nos. 4,716,485 to Yeung and 4,825,319 to Andreas also describe audio cassette player head cleaners. In each of these patents, a circular cleaning pad is rotated such that a point on the face of the pad traces a circle on the head. A first difficulty with these devices is that the effective speeds of cleaning elements at different radial locations from the center of the pad will cause different cleaning effectiveness, with the center element having virtually no cleaning effect. A second difficulty is that cleaning pads will not produce enough scrubbing action to remove brown stain. A third difficulty is an inability to effectively clean head bleed slots. A fourth difficulty is static electricity build-up.
U.S. Pat. No. 4,631,614 to Davis et al. describes a device for cleaning computer heads. The device uses a cam action to drive a cleaning pad in an oscillating vertical stroke. The use of a cleaning pad and the cam mechanism will not produce enough scrubbing action to remove brown stain. Also static electrical build-up may occur.
What is needed is a device for mechanically cleaning a magnetic recording head. The device should scrub the head uniformly to prevent uneven wearing. The device must also remove debris from head bleed slots. Furthermore, a means must be provided to remove any static electricity that may result from cleaning to prevent damage to tape deck electronics.